Harmonic profile optimization in multilevel inverter using soft computing techniques

Abstract

Power system needs reliable with good quality of supply to meet the demand of consumers. The presence of harmonics in electrical power system leads to voltage distortion that may affect the equipment and loads connected to it. Power quality is the term used to measure the voltage quality and current quality across source as well as load terminal. Poor power quality in the supply system can lead to equipment damage or excess heating and in medical electronic equipment, it leads to wrong medical diagnosis. Hence maintaining high quality power is an important need in any system. To overcome the above problem, multilevel inverter receive more attention due to their increasing utilization in power industry for getting quality power. The need of Multi Level Inverter (MLI) is to provide a more output power from voltage source of medium size.Multilevel inverter is classified as multilevel with common DCsource such as diode clamped and flying capacitor and multilevel with isolated DC source like cascade. Among the familiar topologies, the most popular one is cascaded multilevel inverter. It exhibits several attractive features such as simple circuit layout, less component counts, modular in structure and avoid unbalance capacitor voltage problem. But the number of output level increases, the circuit becomes bulky and control will be more complicated due to increase in the number of power devices. So the first part of my research work is to design a new topology or select the optimum topology based on basic Cascaded H-Bridge with less number of switches. In this thesis, new symmetric multilevel inverter topology is proposed and their performance was analysed by MATLAB-SIMULINK software. newline